The present invention relates to a shuttle valve device for selecting one of a plurality of hydraulic pressures, for example, the highest pressure.
A shuttle valve device is known from Japanese Patent Application Laid-Open Nos. 54-115421, 61-36568 and 61-233273. The known shuttle valve device comprises a device body which is composed of a plurality of blocks connected to each other in a stacked fashion. A plurality of shuttle valves are arranged respectively within accommodating spaces formed respectively in the blocks. The shuttle valves communicate with each other through passages formed respectively in the blocks or through passages formed respectively between the adjacent blocks.
The above-described conventional shuttle valve device has the following drawbacks. That is, since the plurality of blocks are required, the number of component parts increases. In addition, since a multiplicity of passages are required, the device is complicated in construction. Thus, the manufacturing cost is high.
Further FIG. 16 of the above-mentioned Japanese Patent Application Laid-Open No. 61-36568 shows, as the prior art, a shuttle valve device in which a multiplicity of shuttle valves are incorporated in a device body formed by a single block. However, the shuttle valve device is extremely complicated in arrangement of passages through which the shuttle valves communicate with each other.